You may also want to consider the evolutionary pressure to love certain people in your family.
Do you think it's mere coincidence that massive amounts of oxytocin are necessarily for lactation, giving birth, released after birth, released after orgasm, and that this drug also just happens to create loving emotional bonds?
Seems that evolution is also manipulating our romances and the loves of our lives. On the other hand it's probably good for society that we're chemically manipulated in this fashion. My point is not that 99% of these feelings aren't "real" my point is more of a skeptical nature in that it becomes impossible to figure out how much is "real" and how much is chemical or other mechanisms of signalling.